In 2011 alone, she's starred in two movies, produced a television show for Bravo and campaigned for a third "Sex and the City" film -- all while raising son James Wilkie, 8, and twins Tabitha and Loretta, 2.

"We've been together for 20 years and you have good days, you have decent days, and you have bad days. That's a marriage. That's a relationship. That's a friendship, even; relationships outside the marriage run the same course."

"If you're in it for the long haul and you want meaningful relationships, you are going to go through lots of different periods."

The New York-based actress tells the Telegraph her list of responsibilities has only grown longer with time.

"Going from one to three children is a much bigger adjustment than becoming a mother in the first place," she says. "One child in retrospect seems a cake walk compared to where I stand today." (Parker and Broderick welcomed their twins via surrogate in 2009.)

"Children provide a whole new set of concerns," Parker, 46, adds. "Who knows what I'll be insecure about next week?"